A nosocomial infection or hospital acquired infection (HAI) is an infection acquired in a healthcare facility by a patient admitted for some reason other than that specific infection. HAIs can be acquired in any setting in which healthcare is delivered, including acute care hospitals, ambulatory care settings, and long-term care facilities, such as nursing homes and skilled nursing facilities. Although certain individuals, such as the critically ill, the elderly, young children, and those with compromised immune systems are at greater risk, no patient is immune from the risk of acquiring an infection during a doctor visit or hospital stay.
The pathogens causing significant nosocomial problems include MRSA (methicillin-resistant Staphylococcus aureas), VRE (vancomycin-resistant Enterococcus), and Clostridium difficile (C. difficile). Their importance derives from a combination of resistance to presently available treatments and an ability to rapidly spread in the environment around hospitalized patients. MRSA causes skin and wound infections, pneumonia, and bloodstream infections. VRE is present in bowel and urinary tract infections. C. difficile is also present in bowel infections and presents as severe diarrhea. For each of these pathogens, control with present antibiotics is problematic, if not impossible. The Center for Disease Control (CDC) estimates that in the United States, at least 2 million people become infected with bacteria that are resistant to antibiotics and at least 23,000 people die as a direct result of these infections. Most deaths related to antibiotic resistance happen in healthcare settings such as hospitals and nursing homes.
Guidelines for prevention of nosocomial infection include the observance of aseptic techniques, frequent hand washing between patients, the use of single-use disposable items, patient isolation, and improved air filtration. In addition, high quality cleaning and disinfection of all patient-care areas is important, especially surfaces close to the patient. Contaminated environmental surfaces provide an important potential source for transmission of healthcare associated pathogens, because some pathogens can survive for long periods of time. Bacterial spores of C. difficile, for example, are capable of surviving for up to five months in healthcare facilities.
In view of the above, there is a need to assess cleaning compliance in hospitals, long-term care facilities and other healthcare settings. One such method is a fluorescent marking system to assess the thoroughness of cleaning of environmental surfaces, particularly those designated “high touch objects” (HTOs) by the CDC. In this method, a translucent targeting solution containing a chemical marker that fluoresces under UV light can be applied to HTOs. The dried marking solution is subsequently removed by moistening with a spray disinfectant and wiping with a damp cloth. A hand-held UV light is used to determine whether the marked HTOs in the room have been cleaned.
Use of fluorescent marking systems to audit cleaning efficiency is compromised, however, when the fluorescent mark is not thoroughly removed in the cleaning process. It has been found that current products which use small molecule optical brighteners as fluorophores leave a “ghost” mark under ultraviolet light that cannot be further scrubbed off the surface. Typical optical brighteners have high affinity for surfaces, which becomes problematic on older surfaces, highly porous surfaces, and surfaces cleaned with oxidizing agents (e.g. bleach, peroxide). The presence of pores, scratches, nicks, pitting, and etching in the environmental surface makes it more difficult to completely remove the optical brightener from the surface. Accordingly, there is a need to develop fluorescent marking compositions that do not leave a residue after cleaning.